html, body {
  margin: 0;
  padding: 0;
  width: 100%;
  height: 100%;
}
#app {
  margin: 0 auto;
  padding: 20px;
  width: 100%;
  height: 100%;
  background-color: #fff;
  overflow-x: hidden;
  overflow-y: auto;
  box-sizing: border-box;
}